Samsung C&T Corp shareholders have approved an $8 billion takeover offer from sister firm Cheil Industries in a close-run vote, marking a key win for Samsung Group's founding family as it seeks to pave the way for a leadership transfer at South Korea's biggest conglomerate.

At a heated meeting of shareholders on Friday (July 17), Samsung C&T secured 69.53 per cent of votes cast in favour of the tie-up.

The all-stock offer from Cheil needed the backing of two-thirds of the votes cast to succeed.

The merger consolidates stakes in key group affiliates, including flagship tech giant Samsung Electronics Co, under the control of the heirs of the founding Lee family.

Samsung Group's 73-year-old patriarch, Lee Kun-hee, remains hospitalised following a heart attack last year.

But US activist hedge fund Elliott Associates, which had vociferously opposed the deal as C&T's third-largest shareholder, is expected to remain an irritant for Samsung Group despite Friday's result.

With a 7.1 per cent stake in C&T, Elliott argued that Cheil's offer undervalues the target.

It filed for two injunctions to stop the vote taking place while calling on other shareholders to oppose it in a rare case of strident shareholder activism in South Korea.

Investors and analysts expect Elliott to continue challenging Samsung with lawsuits. The fund would hold more than two per cent in the merged entity based on the terms of the deal.

A C&T official said the merged entity will do its best to reflect shareholders' interests. Shares in both C&T and Cheil fell sharply after the vote, dropping 7.9 per cent and 5.2 per cent respectively by 0455 GMT, as the potential for sweetened bid terms disappeared.

In a statement, the US fund said: "Elliott is disappointed that the takeover appears to have been approved against the wishes of so many independent shareholders and reserves all options at its disposal."

C&T's biggest shareholder, South Korea's National Pension Service (NPS), cast its 11.2 per cent voting stake in favour of the deal, said a person with direct knowledge of the matter, providing decisive support for Samsung.

The NPS declined to comment. - Reuters